mellow yellow vs wheat

mellow yellow

noun

  • Synonym of bananadine 

wheat

noun

  • A light brown colour, like that of wheat. 

  • Any of several cereal grains, of the genus Triticum, that yields flour as used in bakery. 

adj

  • Wheaten, of a light brown colour, like that of wheat. 

How often have the words mellow yellow and wheat occurred in a corpus of books? (source: Google Ngram Viewer )